Stencil sheet and process of producing the same



Patented Aug. 24, 1926.

UNITED STATES,

I 1,591,425 PATENT OFFICE.

JACOB IBLLSKY, OF CHICAGO, ILLINOIS, ASSIGNOB TO B. DICK COMPANY, OF CHICAGO,

ILLINOIS, A CORPORATION OF ILLINOIS.

STENCIL SHEET AN D PROCESS OF PROD'UCING THE SAME.-

No Drawing.

In carrying out the invention, I employ an open, porous base, such as the Japanese.

paper commonly known as yoshina and this I provide with a coating which, when A applied, is mainly cellulose xanthate or v1s-v an organic acid such as butyric or malonio may be used. Such organic acids do not de-x compose the cellulose xanthate, but, used in excess, precipitate them in an insoluble state,

and papers so treated, immediately after the coating is applied, are subject to change on further standing and exposure, due to the spontaneous decomposition of the cellulose xanthates into cellulose and cellulose hydrates. If the neutralization be done with mineral acids, then the cellulose xanthate is immediately converted into cellulose or its hydrates.

In preparing the viscose, I take 100 grams of cotton and soak this for approximately twenty-four hours in 1200 grams of caustic soda solution, such solution containing'18 grams of caustic soda to 100 grams of dis- 85 tilled water. Other caustic alkalis may serve a similar purpose. After such soaking, the cotton is removed from the. solution and pressed to expel the surplus moisture until the original 100 grams of cotton, plus a part 40 of the absorbed solution, weighs approximately 300 grams. This cotton is then put in a closed vessel and allowed to stand for forty-eight hours, after which there is added thereto from 60 to 70 grams of carbonbisulphide. The mass is then stirred or otherwise agitated for a suitable time (four hours will usually be found sufficient), and then 350 grams of a 15% solution of caustlc soda are added and the mass allowed to stand for about twelve hours. It is now soluble, and sufiicient distilled water is added to dissolve the cotton. Such solution is, of course, alkaline, and, for the'purpose of this invention I neutralize (or partially neutralize) the same with an organic acid, such as malic, butyric Application filed December 12, 1923. Serial No. 680,272.

weight) and distilled water (65 or malonic acid, of which, when butyric acid is used, I prefer adding from 40 to 50 grams which ma be used without causing precipitation of t e cotton. The amount of organic acid which may be used at this point 60 and the degree to which the solution may be tempering agent or agents as above mdicated, and this I prefer to prepare and use as a separate bath. Glycerin (30'parts by arts b weight) produce 00d results, alt ough may, if desired, ad d a small portion (say- 5 parts by weight) of a sulphonated oil such as Turkey red oil. With the tempering so lution so formed, I combine a suitable coagulant, for example, 5 parts, by weight, of a commercial 40% solution of formaldehyde- Highly re-active organic compounds such as aldehydes re-act readily not only withcellulose, but many other substances. The formaldehyde here specified may, therefore, be expected to react not only with the cellu lose, but with the various tempering agents used and these reactions may result not only in the combination of the aldehyde with an individual tempering agent, but in the aldehyde combining in such a manner as to cause a union of two or more molecules of any single tempering agent. Equally it may react in such a manner as to cause a union of one tempering agent with another, or of one or more tempering agents with the cellulose and its hydrates. The resulting coagulated coatings, therefore, produced by this rocess, may not be regarded as an individual 100 chemical substance, but, no doubt, is composed of a large number of substances of widely varying chemical composition, which, however, 'form a homogeneous mass.

* In the production of sheets which are thus 105 coated with a cellulose xanthate solution and a tempering agent or a mixture oftempering agents and an aldehyde 0! other highly reactive organic substance, the coating be-- comes almost immediately insoluble in wa- 110 time. (a few hours at ordinary room.tem-- ter, while if the reactive substance be I omitted, the coating will .be water-soluble for a considerable period of time. In fact, this characteristic will persist until by spontaneous changethe xanthate reverts to celluperature) to 1partiall dry or set. They may then similar y be rawn over the top of the tempering and coagulating solution and again hung to set and so completed ready for practical use.

drates.

' In the use, as in a writingmachine or with a stylus, of a stencil sheet employing the invention herein disclosed, should the coat ing prove too hard or otherwise resistant to open readily under the applied pressure, to form the desired stencil characters, the surface of the sheet may be moistened, as by water or a solution of water and glycerin, whereupon the coating will be found to respond readily and efliciently to thepressure of the type or stylus.

It is to be understood that the present invention is not limited to what is technically known as cellulose xanthate or viscose, particularly in view of the decomposition of the material so known into cellulose and its hy- Accordingly, in the broader claims appended hereto, I shall use the word cellu-' lose as including not only cellulose but also its h drates and decomposition products, and t 's regardless of the process by which these may be obtained. Similarly,

' producing substantially similar results.

I claim 18 I Having now described my invention, what I L'In a type-impressible stencil-sheet, a. .base of 'agulated coating includin V 2. In a type-impressib e. stencil-sheet, a

open, porous material having a cocellulose.

base of open, porous material having a coagulat'ed coating including cellulose and a tempering agent.

save where specifically enumerated, the invention 3. In a type-impressible stencil-sheet, a

base of open, porous material having a coatwhich will react therewith as a coagulant,

and a tempering agent.

5. In a type-impressible stencil-sheet, a:

base of open, porous material havmg a, coating including cellulose-and a highly reactive organic substance which acts as a coagulant.

6. In a type-impressible stencil-sheet, a base of open, porous materialhaving a coating including cellulose, a highly reactive organic substance which acts as a coagulant, and a tempering agent.

7. In a type-impressible stencil-sheet, a base of open, porous material having a coating including cellulose treated with an aldehyde which acts as a coagulant.

8. In a type-impressible stencil-sheet, a base of open, porous material having a coating including cellulose treated with an aldea coagulant, and a temhyde which acts as pering agent.

9. In a type-impressible stencil-sheet, a base of open, porous material having a coatngflincludin cellulose, glycerin and a coa ant.

10. In a type-impressible stencil-sheet, .a base of open, porous material having a coating including cellulose glycerin, water and a ixlia ulant.

oi water and a coagulant.

13. The process 0 producing a type-impressible stencil-sheet which involves coating an open,

re lice its water-solubility.

14. The; process of producing a type-ima type-impressible stencil-sheet, a base of open, porous material having a coatorous sheet with a mass contain-' m cellu ose and coagulating said mass to pressible stencil-sheet which involves coatmg an open, porous sheet with a mass containin cellulose and a tempering agentand coagu ating said mass to reduce its watersolubility.

15. The pressible stencil i P ing an open, porous sheet with a mass contaming cellulose and coagulatin said mass to render it substantially insolu 1e.

16. The process of producing a type-impressible stencil-sheet which involves coat-'- ing an open, porous sheet with a mass contaimng cellulose and a'tempering agent and process of producinga .type-imsheet which involves coatcoagulating said mass to render it substantially water-insoluble.

17. The process of producing a type-impressible stencil-sheet which involves coating an open, porous sheet with cellulose and treating said cellulose with an organic coagulant which will combine therewith.

18. The process of producing a type-impressible stencil-sheet which involves coating an open, porous sheet with cellulose and treating said cellulose with a highly reac-- will combine taining cellulose and a tempering agent and treating said cellulose with an aldehyde coagulant.

21. The process of producing a type-im pressible stencil-sheet WhlGll involves coatmg an open, porous sheet with a mass'containing cellulose rendered substantially water-insoluble by treatment with a highly reactive organic coagulant.

22. The process of preparing. a type-impressible stencil-sheet, which consists in coating a' .base of open material with a vwater-soluble substance which spontaneous- 1y becomes impermeable to ink and subjecting such substance to the action of: a coaguant.v I

23. The process of preparing a type-impressible stencil-sheet, which consists in' coating a base of open material with cellu-' lose xanthate and a coagulant.

24. The process of preparing a type-1mpressible stencil-sheet, which consists in v coating 9. base of open material with cellulose xanthate and an aldehyde which acts as a coagulant.

25. The process of preparing a type-impressible stencil-sheet, which consists in coating a base of open material with cellulose xanthate and formaldehyde.

This specification signed 28th day of November, 1923.

JACOB BILSKY. 

